Laboratory Manual

Laboratory Manual

for

Pharmaceutics II

Dr. Ahmed F. Asker, Professor

and Section Leader of Pharmaceutics

College of Pharmacy & Pharmaceutical Sciences

Florida A & M University, Tallahassee

Florida 32307

Revised: 01/05/05
Laboratory Instructions and Regulation

1. Practice good manners in the laboratory at all times.

2. Appropriate lab. Jackets/coats are to be worn to all laboratory sessions.

3. Personal cleanliness and neatness are important. This includes clean lab. Jacket, clean hands, fresh shaves (well groomed), etc.(Do Not wear shorts to the laboratory). No open toe shoes or sandals shall be warn in the lab.

4. All student must have a personal set of metric and apothecary weights. Mark these weights distinctly and permanently so that if they are lost the finder can be readily identified. Students will furnish liquid detergent, cloth or paper towels, and tissues to cry into for their own desk.

5. There should be a minimum of conversation with other students. Avoid unnecessary and loud conversation during lab. time. Do Your Own Work. (save chitchat with your fellow students for before and/or after class time).

6. Balances and other equipment in the laboratory are delicate, and expensive to purchase as well as maintain. Learn how to use the instruments and equipment properly. Take care in cleaning and use to extend the life of your lab. equipment.

7. Keep your desk orderly at all times. Clean your equipment, bottles, desk draw and table top area daily.

8. Keep general laboratory area neat and clean. As a reflection of yourself, and a courtesy to your classmates. Pay special attention to sink, floor, shelves, and typing area.

9. Return all stock bottles to the end of your workbench, and special equipment and books to the lab. office when you are finished with them.

10. Do Not place insoluble solids (such as some powder prescriptions), ointments, or oils in the sink. Wrap these substances in paper towels and place them in the trash container. If there is a question pertaining to disposal ask the instructor or lab. personnel.

11. Never work in a laboratory section other than your own without first obtaining permission for the Instructor in charge of the lab.

Remember - It is the primary responsibility of the instructor to assist you in learning the proper techniques and practices that will equip you to be a good Pharmacist/Pharm. D.

They are there to help you as well as all other students in the laboratory. They have authority to issue orders concerning work and conduct in the laboratory.

Laboratory Procedure

1. Laboratory questions sheets are to be completed before the laboratory period ends. Amount of ingredients, used, doses and procedures must be entered in ink or typewritten. All of the question for the day’s assignments should be answered. The instructor will check these question sheets during the laboratory period.

2. A label on or under the container must identify any preparation on or in your desk. Unidentified preparation will be confiscated and/or disposed of by the instructor.

3. After the preparations have been graded and handed back, the contents should be properly disposed of by dumping in proper receptacle, or flushed by drain. Do Not take any product out of the laboratory for personal use unless permission is obtained from the instructor in charge.

Experiment I

Density and Porosities of Powders

The purpose of this experiment is to determine the densities and porosities of ingredients in a bulk powder prescription.

Prescription

S.M. Smog, M.D.

264 Washington Ave. Big City, U.S.A.

Name: Mr. A. Fay Date:

Address: 22 Brigs Ave.

Calc. Carbonate 12.5 gm.

Mgo, lt. 12.5 gm

Sodium bicarbonate 5.0 gm.

Flavor oil 0.5 ml

M & Ft Powder

Sig. ss in water a.c.

Refill

Signed:

Procedure:

1. Preparation.

(a) Weigh out the calcium carbonate and place it in a cylindrical graduated Cylinder. Gently tap the cylinder three (3) times from 1” high to the counter top.

(b) Note the total volume and record on the data sheet. This is the bulk volume (Vb). Carry out the calculations on the data sheet.

2. Dispensing the Prescription.

(a) Mix the ingredients of the powder by geometric dilution*, adding the flavor oil as you mix.

(b) Place the bulk powder in a prescription carton. Properly label and hand in the prescription.

*Note Geometric dilution, is a technique involving the blending of materials in small portions to insure that the mixture is consistent throughout. This will be demonstrated by the instructor.

Data and Calculation Sheet

Calcium Carbonate

Magnesium Oxide (Light)

True Density / 2.72 g/cc / 3.65g/cc
Bulk Volume of 12.5 gm. =Vb
Bulk Density = wt.
Vb
True Volume = wt. = Vp
True Density
Void Volume
v = Vb - Vp
Porosity
e = v
Vb
Specific Bulk Density
(Bulikiness)
1/Bulk Density

Experiment II

Evaluating Flow Properties of Solids

The purpose of the following exercise is to evaluate the flowability of calcium carbonate (powder) and sucrose (granular), and to determine their bulk densities and porosities.

Procedure:

1. Flowability: Determined by the angle of repose of each of calcium carbonate and sucrose, using the “Fixed Funnel and Free-Standing Cone” Technique as follows:

(a) A funnel with the end of the stem cut perpendicular to the axis of symmetry is secured with its tip at a given height (H), (e.g. 1.5 cm.) above graph paper placed on a flat horizontal surface.

(b) Carefully pour the powder (CaCO3) through the funnel until the apex of the conical pile formed just reaches the tip of the funnel.

(c) Determine the mean diameter* of the base of the powder cone for three different diameter readings from three different points of reference on the circumference of the base.

*note the diameter is equal twice the radius or (2R)

(d) Calculate the tangent of the angle of repose;

Tan c = H Where c = angle of repose

(e) Find our from the tables the corresponding value of the angle.

(f) Repeat the above three times and determine the value of the angle of repose of the four trials.

(g) Repeat (a) through (f) for Sucrose.

2. Bulk Density and Porosity:

(a) Weigh out 25g of each CaCO3 and Sucrose. Carry out the instructions for determining Bulk Density and Porosity as you did in the previous experiment.

(b) Note and record the totals for each chemical in chart provided.

Data and Calculation sheet

Flowibility:

Experiment / 2R / R / Tan µ =
H / µ
(1) / (2) / (3) / Avg. / (Avg.) / R avg.
(1)
(2)
(3)
(4)

Mean value of µ

Data and Calculation Sheet

Calcium Carbonate /

Sucrose

True Density / 2.72 gm./cc / 1.587gm./cc
Bulk Volume of 25 gm. =Vb
Bulk Density = wt.
Vb
True Volume = wt. = Vp
True Density
Void Volume
v = Vb - Vp
Porosity
e = v
Vb
Specific Bulk Density
(Bulkiness’)
1/Bulk Density

Questions:

1. Why should powder which are to be compress into tablets or filled in capsules have free flowing properties?

2. Bismuth subcarbonate (heavy) has a bulk density of 1.01 g/cc., and a true density of 5.9g/cc. Therefore, bismuth subcarbonate (light) should have: (Circle one)

(a) a bulk density that is = , , or 1.0, and

(b) a true density that is = , , or 6.9.

3. Why is light MgO preferred for administration in liquids?

4. If 200 mg. of a drug is to be weighed on a balance with a sensitivity requirement of 5mg, calculate the percentage of possible error.

5. If the permissible error is 5% and the sensitivity requirement of the balance is 6mg, calculate the smallest amount that can be weighed within this limit of error.

Experiment III

A Baby Powder Preparation

The purposes of these exercises are to develop a proficiency in compounding a bulk powder. As well as study different techniques of geometric dilution, and to develop a proficiency in calculation of possible percentage error for weighing.

Study Assignment:

1. E. Parrott, - Powder, Pharmaceutical Technology, pp. 58-63

2. E. Parrott, and W. Seain, - Matroloy, Experimental Pharm. Technology, pp. 4-9.

Rx Amount used:

Methylbenzethonium Chloride 0.05% (10% Triturated*)

Zinc Oxide Ʒ ii

Starch ' ii

Talcum, c.s. ad ℥ i

Dispense in a sprinkling - type box. Sig. Admin. b. i. d.

P.S. Drugs and Chemicals should be in an impalpable form before mixing.

* The process of grinding a drug in a mortar with a pestle to reduce its particle size is termed trituration. A type of pharmaceutical preparation termed a trituration is a powder mixture usually containing 10% W/W of a potent medicinal substance in a vehicle of lactose or other suitable dilutent. Triturations provide a convenient means whereby pharmacist can accurately obtain small amounts of potent drugs. For example 50 mg. of a potent drug may be obtained by weighing 500mg. of 10%W/W trituration of that drug.

The technique of mixing a small amount of drug with a relatively large amount of diluent is called geometric dilution. Geometric dilution may also be used in mixing powders consisting of several ingredients. The non-potent ingredients are treated as diluents.

Procedure:

Weigh and place the active ingredient in a glass mortar. Weigh the diluent and place it aside. Add a volume of the diluent (by visual estimation) equal to volume of active ingredient and mix until a uniform mixture is obtained. Add an additional volume of diluent (by visual estimation) equal in volume to the homogeneous mixture in the mortar. Continue to mix until uniform. Repeat this procedure, adding each time as much diluent as there is homogeneous mixture in the mortar, until all the diluent is used (mix by the technique demonstrated).

Ingredients Weighed: maximum potential error in each weighing (Balance sensitivity gr. 1/8)

Methylbenzethonium Chloride (Trituration)

Zinc Oxide

Starch

Talcum

Total maximum potential error:

Percentage error = Sensitivity x 100

Quantity Weighed

Medical category of Methylbenzethonium Chloride (N.F.)

Questions: Calculation of powder % error.

1. Assuming the sensitivity of your balance to be gr. 1/6 (or 10 mg.) calculate the maximum potential error of each of the following weighings:

(a) gr. 1/6

(b) gr. ½

(d) ' i

(e) 100 mg.

(f) 0.5 gm.

2. Give two advantages of solid dosage form over a liquid dosage forms.

Experiment IV

Divided Powder

The Purpose of this exercise is to develop proficiency in compounding the individual dosage form of powder and to understand the composition of some o-t-c antacids.

Rx Amount used:

Sodium Bicarbonate (NaHCO3) gr. iv

Precipitated Calcium Carbonate (Ca O3) gr. vi

Peppermint Oil gtt. ss

M. ft. chart #1

D.T.D. #XVIII

label: Antacid Powder No. 1

Procedure: Record chronologically the procedure used:

Rx Amount used:

Al (OH)3 1 5

Magnesium trisilicate 4 5

Menthol 0 03

M. ft. Chart #15

Label: Antacid Powder No. 2

Procedure: Record chronologically the procedure used:

Preparation Of Powders As Individual Doses

The purpose of this demonstration is to show the technique of compounding and dispensing the individual dosage from powders.

After weighing, comminuting and mixing of ingredients are completed, the powder must be accurately divided into the prescribed number of doses. In order to achieve accuracy consistent with the other steps in the compounding, each dose should be weighed individually and transferred to a powder paper. The number of powder paper should correspond to the number of doses being prepared.

The powders are dispensed in a powder box, usually in a hinge type. There are many sizes available, identified by the number and No. 4-6 are most often used. Since the boxes are of different heights a trail folding has to be performed first.

Fold down a long edge of the weighing paper approximately ¼” for the 5 or 6 powder box. Bring the lower edge of the paper to the creased line under the top fold. Press down the latter. Holding down the fold with both thumbs and index fingers pull the top creased edge toward yourself until it divides the paper approximately in half. A new top is thus made. The correct line for this fold will depend on the style and the height of the powder box to be used. The powder should be slightly higher (ab. 1/8”) than the edge of the box so that they can be picked out easily.

Now fold the ends of the powder paper by pressing equal lengths of them down while gently squeezing the sides of the box. Holding securely the folded powders in fingers, place the paper on desk, and crease sharply the end folds with the spatula. Note, the center of the powder paper in not creased in order to insure the even packing to the box later. The folded paper is place vertically into the box to check for proper height. If the height has to be adjusted repeat the folding until proper size in obtained. Use this paper as a guide for future folding.

Using about six papers at a time make about ¼” fold and crease them with the spatula, If too many papers are folded at one time variation in the depth may result. Place the paper on the prescription counter (usually left of the balance) in a uniform fashion so that the tops will be away from the compounder. For example, it 12 powders are compounded place 3 rows of four papers or 2 rows of 6 papers each. Remove ingredients from the mortar onto paper in front of the balance and set the balance in equilibrium with weighing papers on the pans. Place the rider in proper position and weigh the required amounts. Using the same powder paper during all weighings transfer each time the weighed amount to the center of each paper.